"A Roman comes and orders them to stop: “You were ordered to punish him, not to scourge him to death.” This is but the first instance where Romans are depicted as having a conscience, or at least a limit to what they will inflict on a person."
It had nothing to do with conscience. A person who was (possibly) subject to crucifixion was NOT to be beaten to death before crucifixion; any soldier who did so took his place on the cross! In the case of Jesus, the soldiers did not know what Pilate's decision would be, therefore they dared not kill Jesus with the whip.
Bingo. The Romans even gave the crucified a mixture of wine and drugs, not because they wanted to ease their pain, but because they wanted the person to be alive to endure more pain. Also, the Gospels tell us Jesus didn't have to carry the cross all the way. Not because the Romans saw Jesus was tired and wanted to be nice guys and give him a break (the way this blogger paints it), but because they didn't want Jesus to die too soon. All this is hardly evidence of Gibson paint the Romans as nice guys and the priests as bad guys.